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Sync getcap() with FreeBSD:
[dragonfly.git] / lib / libc / gen / getcap.c
blob19fc805021c95efcd0c6c94926a7759e8ad4b310
1 /*-
2 * Copyright (c) 1992, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Casey Leedom of Lawrence Livermore National Laboratory.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * @(#)getcap.c 8.3 (Berkeley) 3/25/94
33 * $FreeBSD: src/lib/libc/gen/getcap.c,v 1.20 2007/01/09 00:27:53 imp Exp $
34 * $DragonFly: src/lib/libc/gen/getcap.c,v 1.7 2005/11/19 22:32:53 swildner Exp $
35 */
36
37 #include "namespace.h"
38 #include <sys/types.h>
39
40 #include <ctype.h>
41 #include <errno.h>
42 #include <fcntl.h>
43 #include <limits.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <unistd.h>
48 #include "un-namespace.h"
49
50 #include <db.h>
51
52 #define BFRAG 1024
53 #define BSIZE 1024
54 #define ESC ('[' & 037) /* ASCII ESC */
55 #define MAX_RECURSION 32 /* maximum getent recursion */
56 #define SFRAG 100 /* cgetstr mallocs in SFRAG chunks */
57
58 #define RECOK (char)0
59 #define TCERR (char)1
60 #define SHADOW (char)2
61
62 static size_t topreclen; /* toprec length */
63 static char *toprec; /* Additional record specified by cgetset() */
64 static int gottoprec; /* Flag indicating retrieval of toprecord */
65
66 static int cdbget(DB *, char **, const char *);
67 static int getent(char **, u_int *, char **, int, const char *, int, char *);
68 static int nfcmp(char *, char *);
69
70 /*
71 * Cgetset() allows the addition of a user specified buffer to be added
72 * to the database array, in effect "pushing" the buffer on top of the
73 * virtual database. 0 is returned on success, -1 on failure.
74 */
75 int
76 cgetset(const char *ent)
77 {
78 if (ent == NULL) {
79 if (toprec)
80 free(toprec);
81 toprec = NULL;
82 topreclen = 0;
83 return (0);
84 }
85 topreclen = strlen(ent);
86 if ((toprec = malloc (topreclen + 1)) == NULL) {
87 errno = ENOMEM;
88 return (-1);
89 }
90 gottoprec = 0;
91 strcpy(toprec, ent);
92 return (0);
93 }
94
95 /*
96 * Cgetcap searches the capability record buf for the capability cap with
97 * type `type'. A pointer to the value of cap is returned on success, NULL
98 * if the requested capability couldn't be found.
99 *
100 * Specifying a type of ':' means that nothing should follow cap (:cap:).
101 * In this case a pointer to the terminating ':' or NUL will be returned if
102 * cap is found.
103 *
104 * If (cap, '@') or (cap, terminator, '@') is found before (cap, terminator)
105 * return NULL.
106 */
107 char *
108 cgetcap(char *buf, const char *cap, int type)
109 {
110 char *bp;
111 const char *cp;
112
113 bp = buf;
114 for (;;) {
115 /*
116 * Skip past the current capability field - it's either the
117 * name field if this is the first time through the loop, or
118 * the remainder of a field whose name failed to match cap.
119 */
120 for (;;)
121 if (*bp == '\0')
122 return (NULL);
123 else
124 if (*bp++ == ':')
125 break;
126
127 /*
128 * Try to match (cap, type) in buf.
129 */
130 for (cp = cap; *cp == *bp && *bp != '\0'; cp++, bp++)
131 continue;
132 if (*cp != '\0')
133 continue;
134 if (*bp == '@')
135 return (NULL);
136 if (type == ':') {
137 if (*bp != '\0' && *bp != ':')
138 continue;
139 return(bp);
140 }
141 if (*bp != type)
142 continue;
143 bp++;
144 return (*bp == '@' ? NULL : bp);
145 }
146 /* NOTREACHED */
147 }
148
149 /*
150 * Cgetent extracts the capability record name from the NULL terminated file
151 * array db_array and returns a pointer to a malloc'd copy of it in buf.
152 * Buf must be retained through all subsequent calls to cgetcap, cgetnum,
153 * cgetflag, and cgetstr, but may then be free'd. 0 is returned on success,
154 * -1 if the requested record couldn't be found, -2 if a system error was
155 * encountered (couldn't open/read a file, etc.), and -3 if a potential
156 * reference loop is detected.
157 */
158 int
159 cgetent(char **buf, char **db_array, const char *name)
160 {
161 u_int dummy;
162
163 return (getent(buf, &dummy, db_array, -1, name, 0, NULL));
164 }
165
166 /*
167 * Getent implements the functions of cgetent. If fd is non-negative,
168 * *db_array has already been opened and fd is the open file descriptor. We
169 * do this to save time and avoid using up file descriptors for tc=
170 * recursions.
171 *
172 * Getent returns the same success/failure codes as cgetent. On success, a
173 * pointer to a malloc'ed capability record with all tc= capabilities fully
174 * expanded and its length (not including trailing ASCII NUL) are left in
175 * *cap and *len.
176 *
177 * Basic algorithm:
178 * + Allocate memory incrementally as needed in chunks of size BFRAG
179 * for capability buffer.
180 * + Recurse for each tc=name and interpolate result. Stop when all
181 * names interpolated, a name can't be found, or depth exceeds
182 * MAX_RECURSION.
183 */
184 static int
185 getent(char **cap, u_int *len, char **db_array, int fd, const char *name,
186 int depth, char *nfield)
187 {
188 DB *capdbp;
189 char *r_end, *rp, **db_p;
190 int myfd, eof, foundit, retval, clen;
191 char *record, *cbuf;
192 int tc_not_resolved;
193 char pbuf[_POSIX_PATH_MAX];
194
195 rp = NULL;
196 myfd = 0;
197
198 /*
199 * Return with ``loop detected'' error if we've recursed more than
200 * MAX_RECURSION times.
201 */
202 if (depth > MAX_RECURSION)
203 return (-3);
204
205 /*
206 * Check if we have a top record from cgetset().
207 */
208 if (depth == 0 && toprec != NULL && cgetmatch(toprec, name) == 0) {
209 if ((record = malloc (topreclen + BFRAG)) == NULL) {
210 errno = ENOMEM;
211 return (-2);
212 }
213 strcpy(record, toprec);
214 myfd = 0;
215 db_p = db_array;
216 rp = record + topreclen + 1;
217 r_end = rp + BFRAG;
218 goto tc_exp;
219 }
220 /*
221 * Allocate first chunk of memory.
222 */
223 if ((record = malloc(BFRAG)) == NULL) {
224 errno = ENOMEM;
225 return (-2);
226 }
227 r_end = record + BFRAG;
228 foundit = 0;
229 /*
230 * Loop through database array until finding the record.
231 */
232
233 for (db_p = db_array; *db_p != NULL; db_p++) {
234 eof = 0;
235
236 /*
237 * Open database if not already open.
238 */
239
240 if (fd >= 0) {
241 lseek(fd, (off_t)0, SEEK_SET);
242 myfd = 0;
243 } else {
244 snprintf(pbuf, sizeof(pbuf), "%s.db", *db_p);
245 if ((capdbp = dbopen(pbuf, O_RDONLY, 0, DB_HASH, 0))
246 != NULL) {
247 free(record);
248 retval = cdbget(capdbp, &record, name);
249 if (retval < 0) {
250 /* no record available */
251 capdbp->close(capdbp);
252 return (retval);
253 }
254 /* save the data; close frees it */
255 clen = strlen(record);
256 cbuf = malloc(clen + 1);
257 memcpy(cbuf, record, clen + 1);
258 if (capdbp->close(capdbp) < 0) {
259 free(cbuf);
260 return (-2);
261 }
262 *len = clen;
263 *cap = cbuf;
264 return (retval);
265 } else {
266 fd = _open(*db_p, O_RDONLY, 0);
267 if (fd < 0)
268 continue;
269 myfd = 1;
270 }
271 }
272 /*
273 * Find the requested capability record ...
274 */
275 {
276 char buf[BUFSIZ];
277 char *b_end, *bp;
278 int c;
279
280 /*
281 * Loop invariants:
282 * There is always room for one more character in record.
283 * R_end always points just past end of record.
284 * Rp always points just past last character in record.
285 * B_end always points just past last character in buf.
286 * Bp always points at next character in buf.
287 */
288 b_end = buf;
289 bp = buf;
290 for (;;) {
291
292 /*
293 * Read in a line implementing (\, newline)
294 * line continuation.
295 */
296 rp = record;
297 for (;;) {
298 if (bp >= b_end) {
299 int n;
300
301 n = _read(fd, buf, sizeof(buf));
302 if (n <= 0) {
303 if (myfd)
304 _close(fd);
305 if (n < 0) {
306 free(record);
307 return (-2);
308 } else {
309 fd = -1;
310 eof = 1;
311 break;
312 }
313 }
314 b_end = buf+n;
315 bp = buf;
316 }
317
318 c = *bp++;
319 if (c == '\n') {
320 if (rp > record && *(rp-1) == '\\') {
321 rp--;
322 continue;
323 } else
324 break;
325 }
326 *rp++ = c;
327
328 /*
329 * Enforce loop invariant: if no room
330 * left in record buffer, try to get
331 * some more.
332 */
333 if (rp >= r_end) {
334 u_int pos;
335 size_t newsize;
336
337 pos = rp - record;
338 newsize = r_end - record + BFRAG;
339 record = reallocf(record, newsize);
340 if (record == NULL) {
341 errno = ENOMEM;
342 if (myfd)
343 _close(fd);
344 return (-2);
345 }
346 r_end = record + newsize;
347 rp = record + pos;
348 }
349 }
350 /* loop invariant let's us do this */
351 *rp++ = '\0';
352
353 /*
354 * If encountered eof check next file.
355 */
356 if (eof)
357 break;
358
359 /*
360 * Toss blank lines and comments.
361 */
362 if (*record == '\0' || *record == '#')
363 continue;
364
365 /*
366 * See if this is the record we want ...
367 */
368 if (cgetmatch(record, name) == 0) {
369 if (nfield == NULL || !nfcmp(nfield, record)) {
370 foundit = 1;
371 break; /* found it! */
372 }
373 }
374 }
375 }
376 if (foundit)
377 break;
378 }
379
380 if (!foundit) {
381 free(record);
382 return (-1);
383 }
384
385 /*
386 * Got the capability record, but now we have to expand all tc=name
387 * references in it ...
388 */
389 tc_exp: {
390 char *newicap, *s;
391 int newilen;
392 u_int ilen;
393 int diff, iret, tclen;
394 char *icap, *scan, *tc, *tcstart, *tcend;
395
396 /*
397 * Loop invariants:
398 * There is room for one more character in record.
399 * R_end points just past end of record.
400 * Rp points just past last character in record.
401 * Scan points at remainder of record that needs to be
402 * scanned for tc=name constructs.
403 */
404 scan = record;
405 tc_not_resolved = 0;
406 for (;;) {
407 if ((tc = cgetcap(scan, "tc", '=')) == NULL)
408 break;
409
410 /*
411 * Find end of tc=name and stomp on the trailing `:'
412 * (if present) so we can use it to call ourselves.
413 */
414 s = tc;
415 for (;;)
416 if (*s == '\0')
417 break;
418 else
419 if (*s++ == ':') {
420 *(s - 1) = '\0';
421 break;
422 }
423 tcstart = tc - 3;
424 tclen = s - tcstart;
425 tcend = s;
426
427 iret = getent(&icap, &ilen, db_p, fd, tc, depth+1,
428 NULL);
429 newicap = icap; /* Put into a register. */
430 newilen = ilen;
431 if (iret != 0) {
432 /* an error */
433 if (iret < -1) {
434 if (myfd)
435 _close(fd);
436 free(record);
437 return (iret);
438 }
439 if (iret == 1)
440 tc_not_resolved = 1;
441 /* couldn't resolve tc */
442 if (iret == -1) {
443 *(s - 1) = ':';
444 scan = s - 1;
445 tc_not_resolved = 1;
446 continue;
447
448 }
449 }
450 /* not interested in name field of tc'ed record */
451 s = newicap;
452 for (;;)
453 if (*s == '\0')
454 break;
455 else
456 if (*s++ == ':')
457 break;
458 newilen -= s - newicap;
459 newicap = s;
460
461 /* make sure interpolated record is `:'-terminated */
462 s += newilen;
463 if (*(s-1) != ':') {
464 *s = ':'; /* overwrite NUL with : */
465 newilen++;
466 }
467
468 /*
469 * Make sure there's enough room to insert the
470 * new record.
471 */
472 diff = newilen - tclen;
473 if (diff >= r_end - rp) {
474 u_int pos, tcpos, tcposend;
475 size_t newsize;
476
477 pos = rp - record;
478 newsize = r_end - record + diff + BFRAG;
479 tcpos = tcstart - record;
480 tcposend = tcend - record;
481 record = reallocf(record, newsize);
482 if (record == NULL) {
483 errno = ENOMEM;
484 if (myfd)
485 _close(fd);
486 free(icap);
487 return (-2);
488 }
489 r_end = record + newsize;
490 rp = record + pos;
491 tcstart = record + tcpos;
492 tcend = record + tcposend;
493 }
494
495 /*
496 * Insert tc'ed record into our record.
497 */
498 s = tcstart + newilen;
499 bcopy(tcend, s, rp - tcend);
500 bcopy(newicap, tcstart, newilen);
501 rp += diff;
502 free(icap);
503
504 /*
505 * Start scan on `:' so next cgetcap works properly
506 * (cgetcap always skips first field).
507 */
508 scan = s-1;
509 }
510
511 }
512 /*
513 * Close file (if we opened it), give back any extra memory, and
514 * return capability, length and success.
515 */
516 if (myfd)
517 _close(fd);
518 *len = rp - record - 1; /* don't count NUL */
519 if (r_end > rp)
520 if ((record =
521 reallocf(record, (size_t)(rp - record))) == NULL) {
522 errno = ENOMEM;
523 return (-2);
524 }
525
526 *cap = record;
527 if (tc_not_resolved)
528 return (1);
529 return (0);
530 }
531
532 static int
533 cdbget(DB *capdbp, char **bp, const char *name)
534 {
535 DBT key, data;
536 char *namebuf;
537
538 namebuf = strdup(name);
539 if (namebuf == NULL)
540 return (-2);
541 key.data = namebuf;
542 key.size = strlen(namebuf);
543
544 for (;;) {
545 /* Get the reference. */
546 switch(capdbp->get(capdbp, &key, &data, 0)) {
547 case -1:
548 free(namebuf);
549 return (-2);
550 case 1:
551 free(namebuf);
552 return (-1);
553 }
554
555 /* If not an index to another record, leave. */
556 if (((char *)data.data)[0] != SHADOW)
557 break;
558
559 key.data = (char *)data.data + 1;
560 key.size = data.size - 1;
561 }
562
563 *bp = (char *)data.data + 1;
564 free(namebuf);
565 return (((char *)(data.data))[0] == TCERR ? 1 : 0);
566 }
567
568 /*
569 * Cgetmatch will return 0 if name is one of the names of the capability
570 * record buf, -1 if not.
571 */
572 int
573 cgetmatch(const char *buf, const char *name)
574 {
575 const char *np, *bp;
576
577 if (name == NULL || *name == '\0')
578 return -1;
579
580 /*
581 * Start search at beginning of record.
582 */
583 bp = buf;
584 for (;;) {
585 /*
586 * Try to match a record name.
587 */
588 np = name;
589 for (;;)
590 if (*np == '\0')
591 if (*bp == '|' || *bp == ':' || *bp == '\0')
592 return (0);
593 else
594 break;
595 else
596 if (*bp++ != *np++)
597 break;
598
599 /*
600 * Match failed, skip to next name in record.
601 */
602 bp--; /* a '|' or ':' may have stopped the match */
603 for (;;)
604 if (*bp == '\0' || *bp == ':')
605 return (-1); /* match failed totally */
606 else
607 if (*bp++ == '|')
608 break; /* found next name */
609 }
610 }
611
612
613
614
615
616 int
617 cgetfirst(char **buf, char **db_array)
618 {
619 cgetclose();
620 return (cgetnext(buf, db_array));
621 }
622
623 static FILE *pfp;
624 static int slash;
625 static char **dbp;
626
627 int
628 cgetclose(void)
629 {
630 if (pfp != NULL) {
631 fclose(pfp);
632 pfp = NULL;
633 }
634 dbp = NULL;
635 gottoprec = 0;
636 slash = 0;
637 return(0);
638 }
639
640 /*
641 * Cgetnext() gets either the first or next entry in the logical database
642 * specified by db_array. It returns 0 upon completion of the database, 1
643 * upon returning an entry with more remaining, and -1 if an error occurs.
644 */
645 int
646 cgetnext(char **bp, char **db_array)
647 {
648 size_t len;
649 int done, hadreaderr, i, savederrno, status;
650 char *cp, *line, *rp, *np, buf[BSIZE], nbuf[BSIZE];
651 u_int dummy;
652
653 savederrno = 0;
654
655 if (dbp == NULL)
656 dbp = db_array;
657
658 if (pfp == NULL && (pfp = fopen(*dbp, "r")) == NULL) {
659 cgetclose();
660 return (-1);
661 }
662 for(;;) {
663 if (toprec && !gottoprec) {
664 gottoprec = 1;
665 line = toprec;
666 } else {
667 line = fgetln(pfp, &len);
668 if (line == NULL && pfp) {
669 hadreaderr = ferror(pfp);
670 if (hadreaderr)
671 savederrno = errno;
672 fclose(pfp);
673 pfp = NULL;
674 if (hadreaderr) {
675 cgetclose();
676 errno = savederrno;
677 return (-1);
678 } else {
679 if (*++dbp == NULL) {
680 cgetclose();
681 return (0);
682 } else if ((pfp =
683 fopen(*dbp, "r")) == NULL) {
684 cgetclose();
685 return (-1);
686 } else
687 continue;
688 }
689 } else
690 line[len - 1] = '\0';
691 if (len == 1) {
692 slash = 0;
693 continue;
694 }
695 if (isspace((unsigned char)*line) ||
696 *line == ':' || *line == '#' || slash) {
697 if (line[len - 2] == '\\')
698 slash = 1;
699 else
700 slash = 0;
701 continue;
702 }
703 if (line[len - 2] == '\\')
704 slash = 1;
705 else
706 slash = 0;
707 }
708
709
710 /*
711 * Line points to a name line.
712 */
713 i = 0;
714 done = 0;
715 np = nbuf;
716 for (;;) {
717 for (cp = line; *cp != '\0'; cp++) {
718 if (*cp == ':') {
719 *np++ = ':';
720 done = 1;
721 break;
722 }
723 if (*cp == '\\')
724 break;
725 *np++ = *cp;
726 }
727 if (done) {
728 *np = '\0';
729 break;
730 } else { /* name field extends beyond the line */
731 line = fgetln(pfp, &len);
732 if (line == NULL && pfp) {
733 /* Name extends beyond the EOF! */
734 hadreaderr = ferror(pfp);
735 if (hadreaderr)
736 savederrno = errno;
737 fclose(pfp);
738 pfp = NULL;
739 if (hadreaderr) {
740 cgetclose();
741 errno = savederrno;
742 return (-1);
743 } else {
744 cgetclose();
745 return (-1);
746 }
747 } else
748 line[len - 1] = '\0';
749 }
750 }
751 rp = buf;
752 for(cp = nbuf; *cp != '\0'; cp++)
753 if (*cp == '|' || *cp == ':')
754 break;
755 else
756 *rp++ = *cp;
757
758 *rp = '\0';
759 /*
760 * XXX
761 * Last argument of getent here should be nbuf if we want true
762 * sequential access in the case of duplicates.
763 * With NULL, getent will return the first entry found
764 * rather than the duplicate entry record. This is a
765 * matter of semantics that should be resolved.
766 */
767 status = getent(bp, &dummy, db_array, -1, buf, 0, NULL);
768 if (status == -2 || status == -3)
769 cgetclose();
770
771 return (status + 1);
772 }
773 /* NOTREACHED */
774 }
775
776 /*
777 * Cgetstr retrieves the value of the string capability cap from the
778 * capability record pointed to by buf. A pointer to a decoded, NUL
779 * terminated, malloc'd copy of the string is returned in the char *
780 * pointed to by str. The length of the string not including the trailing
781 * NUL is returned on success, -1 if the requested string capability
782 * couldn't be found, -2 if a system error was encountered (storage
783 * allocation failure).
784 */
785 int
786 cgetstr(char *buf, const char *cap, char **str)
787 {
788 u_int m_room;
789 char *bp, *mp;
790 int len;
791 char *mem;
792
793 /*
794 * Find string capability cap
795 */
796 bp = cgetcap(buf, cap, '=');
797 if (bp == NULL)
798 return (-1);
799
800 /*
801 * Conversion / storage allocation loop ... Allocate memory in
802 * chunks SFRAG in size.
803 */
804 if ((mem = malloc(SFRAG)) == NULL) {
805 errno = ENOMEM;
806 return (-2); /* couldn't even allocate the first fragment */
807 }
808 m_room = SFRAG;
809 mp = mem;
810
811 while (*bp != ':' && *bp != '\0') {
812 /*
813 * Loop invariants:
814 * There is always room for one more character in mem.
815 * Mp always points just past last character in mem.
816 * Bp always points at next character in buf.
817 */
818 if (*bp == '^') {
819 bp++;
820 if (*bp == ':' || *bp == '\0')
821 break; /* drop unfinished escape */
822 if (*bp == '?') {
823 *mp++ = '\177';
824 bp++;
825 } else
826 *mp++ = *bp++ & 037;
827 } else if (*bp == '\\') {
828 bp++;
829 if (*bp == ':' || *bp == '\0')
830 break; /* drop unfinished escape */
831 if ('0' <= *bp && *bp <= '7') {
832 int n, i;
833
834 n = 0;
835 i = 3; /* maximum of three octal digits */
836 do {
837 n = n * 8 + (*bp++ - '0');
838 } while (--i && '0' <= *bp && *bp <= '7');
839 *mp++ = n;
840 }
841 else switch (*bp++) {
842 case 'b': case 'B':
843 *mp++ = '\b';
844 break;
845 case 't': case 'T':
846 *mp++ = '\t';
847 break;
848 case 'n': case 'N':
849 *mp++ = '\n';
850 break;
851 case 'f': case 'F':
852 *mp++ = '\f';
853 break;
854 case 'r': case 'R':
855 *mp++ = '\r';
856 break;
857 case 'e': case 'E':
858 *mp++ = ESC;
859 break;
860 case 'c': case 'C':
861 *mp++ = ':';
862 break;
863 default:
864 /*
865 * Catches '\', '^', and
866 * everything else.
867 */
868 *mp++ = *(bp-1);
869 break;
870 }
871 } else
872 *mp++ = *bp++;
873 m_room--;
874
875 /*
876 * Enforce loop invariant: if no room left in current
877 * buffer, try to get some more.
878 */
879 if (m_room == 0) {
880 size_t size = mp - mem;
881
882 if ((mem = reallocf(mem, size + SFRAG)) == NULL)
883 return (-2);
884 m_room = SFRAG;
885 mp = mem + size;
886 }
887 }
888 *mp++ = '\0'; /* loop invariant let's us do this */
889 m_room--;
890 len = mp - mem - 1;
891
892 /*
893 * Give back any extra memory and return value and success.
894 */
895 if (m_room != 0)
896 if ((mem = reallocf(mem, (size_t)(mp - mem))) == NULL)
897 return (-2);
898 *str = mem;
899 return (len);
900 }
901
902 /*
903 * Cgetustr retrieves the value of the string capability cap from the
904 * capability record pointed to by buf. The difference between cgetustr()
905 * and cgetstr() is that cgetustr does not decode escapes but rather treats
906 * all characters literally. A pointer to a NUL terminated malloc'd
907 * copy of the string is returned in the char pointed to by str. The
908 * length of the string not including the trailing NUL is returned on success,
909 * -1 if the requested string capability couldn't be found, -2 if a system
910 * error was encountered (storage allocation failure).
911 */
912 int
913 cgetustr(char *buf, const char *cap, char **str)
914 {
915 u_int m_room;
916 char *bp, *mp;
917 int len;
918 char *mem;
919
920 /*
921 * Find string capability cap
922 */
923 if ((bp = cgetcap(buf, cap, '=')) == NULL)
924 return (-1);
925
926 /*
927 * Conversion / storage allocation loop ... Allocate memory in
928 * chunks SFRAG in size.
929 */
930 if ((mem = malloc(SFRAG)) == NULL) {
931 errno = ENOMEM;
932 return (-2); /* couldn't even allocate the first fragment */
933 }
934 m_room = SFRAG;
935 mp = mem;
936
937 while (*bp != ':' && *bp != '\0') {
938 /*
939 * Loop invariants:
940 * There is always room for one more character in mem.
941 * Mp always points just past last character in mem.
942 * Bp always points at next character in buf.
943 */
944 *mp++ = *bp++;
945 m_room--;
946
947 /*
948 * Enforce loop invariant: if no room left in current
949 * buffer, try to get some more.
950 */
951 if (m_room == 0) {
952 size_t size = mp - mem;
953
954 if ((mem = reallocf(mem, size + SFRAG)) == NULL)
955 return (-2);
956 m_room = SFRAG;
957 mp = mem + size;
958 }
959 }
960 *mp++ = '\0'; /* loop invariant let's us do this */
961 m_room--;
962 len = mp - mem - 1;
963
964 /*
965 * Give back any extra memory and return value and success.
966 */
967 if (m_room != 0)
968 if ((mem = reallocf(mem, (size_t)(mp - mem))) == NULL)
969 return (-2);
970 *str = mem;
971 return (len);
972 }
973
974 /*
975 * Cgetnum retrieves the value of the numeric capability cap from the
976 * capability record pointed to by buf. The numeric value is returned in
977 * the long pointed to by num. 0 is returned on success, -1 if the requested
978 * numeric capability couldn't be found.
979 */
980 int
981 cgetnum(char *buf, const char *cap, long *num)
982 {
983 long n;
984 int base, digit;
985 char *bp;
986
987 /*
988 * Find numeric capability cap
989 */
990 bp = cgetcap(buf, cap, '#');
991 if (bp == NULL)
992 return (-1);
993
994 /*
995 * Look at value and determine numeric base:
996 * 0x... or 0X... hexadecimal,
997 * else 0... octal,
998 * else decimal.
999 */
1000 if (*bp == '0') {
1001 bp++;
1002 if (*bp == 'x' || *bp == 'X') {
1003 bp++;
1004 base = 16;
1005 } else
1006 base = 8;
1007 } else
1008 base = 10;
1009
1010 /*
1011 * Conversion loop ...
1012 */
1013 n = 0;
1014 for (;;) {
1015 if ('0' <= *bp && *bp <= '9')
1016 digit = *bp - '0';
1017 else if ('a' <= *bp && *bp <= 'f')
1018 digit = 10 + *bp - 'a';
1019 else if ('A' <= *bp && *bp <= 'F')
1020 digit = 10 + *bp - 'A';
1021 else
1022 break;
1023
1024 if (digit >= base)
1025 break;
1026
1027 n = n * base + digit;
1028 bp++;
1029 }
1030
1031 /*
1032 * Return value and success.
1033 */
1034 *num = n;
1035 return (0);
1036 }
1037
1038
1039 /*
1040 * Compare name field of record.
1041 */
1042 static int
1043 nfcmp(char *nf, char *rec)
1044 {
1045 char *cp, tmp;
1046 int ret;
1047
1048 for (cp = rec; *cp != ':'; cp++)
1049 ;
1050
1051 tmp = *(cp + 1);
1052 *(cp + 1) = '\0';
1053 ret = strcmp(nf, rec);
1054 *(cp + 1) = tmp;
1055
1056 return (ret);
1057 }
DragonFly BSD